For a decade, the security industry has relentlessly shrunk the attack surface: endpoints, networks, cloud, identity, applications. Billions of dollars dedicated to closing gaps.
We’ve gotten remarkably good at it.
But while we built that perimeter, something else was happening. Every day, employees did exactly what they were supposed to do: collaborate with partners, customers, and vendors. Their primary tool? Email.
Every attachment sent became a file permanently outside organizational control. Duplicated. Irrevocable. Invisible.
Nobody called it an attack surface. It was just work.
The Blind Spot in the Security Stack
Here’s a question we ask customers: Can you tell me how much sensitive data left your organization through email last month?
The honest answer, almost universally, is no.
This isn’t a failure of intent. Security teams have deployed DLP, configured secure mail gateways, labeled data with Microsoft Purview. They’ve done everything frameworks recommend and still can’t answer that question. Because their tools were built to prevent data from leaving, not measure what’s already gone.
We call this the collaboration attack surface: the continuously expanding volume of sensitive unstructured data living outside your control, created through the most sanctioned channel in the enterprise.
The math compounds quietly. One email. One sensitive attachment. Three external recipients. Three files permanently beyond reach. No revocation, no audit trail, no visibility. Scale to millions of emails yearly, and exposure is measured in billions of uncontrolled copies.
Every CISO knows this is happening. Until now, no one could prove it.
We Built the Instrument That Was Missing
Today, we’re announcing the eSHARE Collaboration Attack Surface Assessment, a free, 15-day risk assessment providing the first comprehensive, quantified view of email-based data exposure.
We built it because visibility is where every governance journey begins. You can’t reduce a risk you can’t measure.
The assessment answers fundamental Zero Trust questions:
➤ Who is sending and receiving your data
➤ What is being shared (sensitivity, size, type)
➤ Where it’s going (consumer vs. corporate domains)
➤ When it was shared (trends over time)
➤ How files leave (attachments vs. links)
At its center is a single metric: the Collaboration Attack Surface Score, the average file copies created per external recipient. Simple enough for a 30-second board conversation. Precise enough to drive remediation.
A score of 2.0 means 1,000 external recipients have created approximately 2,000 file copies outside your control. No updates. No revocation. No visibility.
That number is your baseline, the starting point for real governance.
Why This Matters Now
We didn’t build this because email is new. We built it because the stakes just changed.
By 2028, Gartner predicts 90% of B2B transactions will be AI-agent intermediated. External data sharing won’t grow linearly. It will explode. AI agents will share data at machine speed, across every boundary.
Organizations that can’t govern what leaves through email, the channel humans control, have no foundation for governing AI agents.
Email governance isn’t a legacy problem. It’s the foundation for everything coming next.
From Visibility to Action
The assessment doesn’t end with a score. It ends with a roadmap.
Every report breaks down sharing activity by sensitivity label, file type, and recipient domain, surfacing concentration risk and the patterns creating greatest exposure.
More importantly, it shows where eSHARE’s Secure Mail Gateway can intervene: automatically converting restricted files to governed, revocable links; enabling view-only access without downloads; revoking access to content already shared.
The assessment makes that delta visible. Before state. After state. The size of the opportunity.
An Invitation
The assessment is free. The only requirement is willingness to examine this blind spot.
Request Your Collaboration Attack Surface Assessment →
The collaboration attack surface has grown in plain sight for decades. We finally have a way to see it, and fix it together.
